drm/amdgpu: wait for IB test on first device open

[ Upstream commit 3bfa8897e4d08f822d1d58cf6cbbffbccef82e08 ]

Instead of delaying that to the first query. Otherwise we could try to use the
SDMA for VM updates before the IB tests are done.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Reviewed-by: Junwei Zhang <Jerry.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>